CODEWITHSUNDEEP
c#
matthew
matthew

Reputation: 1

Why does it say invalid expression?

Why does this not work?

private void btnEquals_Click(object sender, EventArgs e)
{
    if (plusButtonClicked == true)
    {
        total2 = total1 + double.Parse(txtDisplay.Text);
    }
    else if (minusButtonClicked == true);
    {
        total2 = total1 - double.Parse(txtDisplay.Text);
    }
    else if (multiplyButtonClicked == true);
    {
        total2 = total1 * double.Parse(txtDisplay.Text);
    }
    else
    {
        total2 = total1 / double.Parse(txtDisplay.Text);
    }

It works until the second "else if" it says invalid expression else

Upvotes: 0

Views: 3684

Answers (5)

Siten
Siten

Reputation: 4533

Meaning of semicolon after if-else menace you just stop the condition.

Remove ;

and add:

private void btnEquals_Click(object sender, EventArgs e)
{
    if (plusButtonClicked == true)
    {
        total2 = total1 + double.Parse(txtDisplay.Text);
    }
        else if (minusButtonClicked == true)
    {
        total2 = total1 - double.Parse(txtDisplay.Text);
    }
        else if (multiplyButtonClicked == true)
    {
        total2 = total1 * double.Parse(txtDisplay.Text);
    }
        else
    {
        total2 = total1 / double.Parse(txtDisplay.Text);
    }
  }

Upvotes: 0

Javed Akram
Javed Akram

Reputation: 15344

remove semicolon after else-if 

 else if (minusButtonClicked == true);  //remove semicolon

also no need to use ==true in (minusButtonClicked == true)

Upvotes: 1

Rupok
Rupok

Reputation: 2082


private void btnEquals_Click(object sender, EventArgs e) { 
            if (plusButtonClicked == true) 
            { 
                total2 = total1 + double.Parse(txtDisplay.Text); 
            }
            else if (minusButtonClicked == true) 
            { 
                total2 = total1 - double.Parse(txtDisplay.Text); 
            }
            else if (multiplyButtonClicked == true)
            { 
                total2 = total1 * double.Parse(txtDisplay.Text); 
            } 
            else
            { 
                total2 = total1 / double.Parse(txtDisplay.Text);
            }
        }

Upvotes: 0

Chandu
Chandu

Reputation: 82893

Remove semi-colons after the else if's

private void btnEquals_Click(object sender, EventArgs e)
{
    if (plusButtonClicked == true)
    {
        total2 = total1 + double.Parse(txtDisplay.Text);
    }
        else if (minusButtonClicked == true)
    {
        total2 = total1 - double.Parse(txtDisplay.Text);
    }
        else if (multiplyButtonClicked == true)
    {
        total2 = total1 * double.Parse(txtDisplay.Text);
    }
        else
    {
        total2 = total1 / double.Parse(txtDisplay.Text);
    }
  }

Upvotes: 1

Andrew Shepherd
Andrew Shepherd

Reputation: 45222

Because you put a semicolon after the first else-if line.

private void btnEquals_Click(object sender, EventArgs e)
{
    if (plusButtonClicked == true)
    {
        total2 = total1 + double.Parse(txtDisplay.Text);
    }
    else if (minusButtonClicked == true);  // <<== There should not be a semicolon here
    {
        total2 = total1 - double.Parse(txtDisplay.Text);
    }
    else if (multiplyButtonClicked == true); // <<== or here
    {
        total2 = total1 * double.Parse(txtDisplay.Text);
    }
    else
    {
        total2 = total1 / double.Parse(txtDisplay.Text);
    }

Upvotes: 5

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